1 /* 2 * net/sched/sch_prio.c Simple 3-band priority "scheduler". 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 10 * Fixes: 19990609: J Hadi Salim <hadi@nortelnetworks.com>: 11 * Init -- EINVAL when opt undefined 12 */ 13 14 #include <linux/module.h> 15 #include <linux/types.h> 16 #include <linux/kernel.h> 17 #include <linux/string.h> 18 #include <linux/errno.h> 19 #include <linux/skbuff.h> 20 #include <net/netlink.h> 21 #include <net/pkt_sched.h> 22 23 24 struct prio_sched_data 25 { 26 int bands; 27 struct tcf_proto *filter_list; 28 u8 prio2band[TC_PRIO_MAX+1]; 29 struct Qdisc *queues[TCQ_PRIO_BANDS]; 30 }; 31 32 33 static struct Qdisc * 34 prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) 35 { 36 struct prio_sched_data *q = qdisc_priv(sch); 37 u32 band = skb->priority; 38 struct tcf_result res; 39 int err; 40 41 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; 42 if (TC_H_MAJ(skb->priority) != sch->handle) { 43 err = tc_classify(skb, q->filter_list, &res); 44 #ifdef CONFIG_NET_CLS_ACT 45 switch (err) { 46 case TC_ACT_STOLEN: 47 case TC_ACT_QUEUED: 48 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; 49 case TC_ACT_SHOT: 50 return NULL; 51 } 52 #endif 53 if (!q->filter_list || err < 0) { 54 if (TC_H_MAJ(band)) 55 band = 0; 56 return q->queues[q->prio2band[band&TC_PRIO_MAX]]; 57 } 58 band = res.classid; 59 } 60 band = TC_H_MIN(band) - 1; 61 if (band >= q->bands) 62 return q->queues[q->prio2band[0]]; 63 64 return q->queues[band]; 65 } 66 67 static int 68 prio_enqueue(struct sk_buff *skb, struct Qdisc *sch) 69 { 70 struct Qdisc *qdisc; 71 int ret; 72 73 qdisc = prio_classify(skb, sch, &ret); 74 #ifdef CONFIG_NET_CLS_ACT 75 if (qdisc == NULL) { 76 77 if (ret & __NET_XMIT_BYPASS) 78 sch->qstats.drops++; 79 kfree_skb(skb); 80 return ret; 81 } 82 #endif 83 84 ret = qdisc_enqueue(skb, qdisc); 85 if (ret == NET_XMIT_SUCCESS) { 86 sch->bstats.bytes += qdisc_pkt_len(skb); 87 sch->bstats.packets++; 88 sch->q.qlen++; 89 return NET_XMIT_SUCCESS; 90 } 91 if (net_xmit_drop_count(ret)) 92 sch->qstats.drops++; 93 return ret; 94 } 95 96 97 static int 98 prio_requeue(struct sk_buff *skb, struct Qdisc* sch) 99 { 100 struct Qdisc *qdisc; 101 int ret; 102 103 qdisc = prio_classify(skb, sch, &ret); 104 #ifdef CONFIG_NET_CLS_ACT 105 if (qdisc == NULL) { 106 if (ret & __NET_XMIT_BYPASS) 107 sch->qstats.drops++; 108 kfree_skb(skb); 109 return ret; 110 } 111 #endif 112 113 if ((ret = qdisc->ops->requeue(skb, qdisc)) == NET_XMIT_SUCCESS) { 114 sch->q.qlen++; 115 sch->qstats.requeues++; 116 return NET_XMIT_SUCCESS; 117 } 118 if (net_xmit_drop_count(ret)) 119 sch->qstats.drops++; 120 return ret; 121 } 122 123 124 static struct sk_buff *prio_dequeue(struct Qdisc* sch) 125 { 126 struct prio_sched_data *q = qdisc_priv(sch); 127 int prio; 128 129 for (prio = 0; prio < q->bands; prio++) { 130 struct Qdisc *qdisc = q->queues[prio]; 131 struct sk_buff *skb = qdisc->dequeue(qdisc); 132 if (skb) { 133 sch->q.qlen--; 134 return skb; 135 } 136 } 137 return NULL; 138 139 } 140 141 static unsigned int prio_drop(struct Qdisc* sch) 142 { 143 struct prio_sched_data *q = qdisc_priv(sch); 144 int prio; 145 unsigned int len; 146 struct Qdisc *qdisc; 147 148 for (prio = q->bands-1; prio >= 0; prio--) { 149 qdisc = q->queues[prio]; 150 if (qdisc->ops->drop && (len = qdisc->ops->drop(qdisc)) != 0) { 151 sch->q.qlen--; 152 return len; 153 } 154 } 155 return 0; 156 } 157 158 159 static void 160 prio_reset(struct Qdisc* sch) 161 { 162 int prio; 163 struct prio_sched_data *q = qdisc_priv(sch); 164 165 for (prio=0; prio<q->bands; prio++) 166 qdisc_reset(q->queues[prio]); 167 sch->q.qlen = 0; 168 } 169 170 static void 171 prio_destroy(struct Qdisc* sch) 172 { 173 int prio; 174 struct prio_sched_data *q = qdisc_priv(sch); 175 176 tcf_destroy_chain(&q->filter_list); 177 for (prio=0; prio<q->bands; prio++) 178 qdisc_destroy(q->queues[prio]); 179 } 180 181 static int prio_tune(struct Qdisc *sch, struct nlattr *opt) 182 { 183 struct prio_sched_data *q = qdisc_priv(sch); 184 struct tc_prio_qopt *qopt; 185 int i; 186 187 if (nla_len(opt) < sizeof(*qopt)) 188 return -EINVAL; 189 qopt = nla_data(opt); 190 191 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < 2) 192 return -EINVAL; 193 194 for (i=0; i<=TC_PRIO_MAX; i++) { 195 if (qopt->priomap[i] >= qopt->bands) 196 return -EINVAL; 197 } 198 199 sch_tree_lock(sch); 200 q->bands = qopt->bands; 201 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1); 202 203 for (i=q->bands; i<TCQ_PRIO_BANDS; i++) { 204 struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc); 205 if (child != &noop_qdisc) { 206 qdisc_tree_decrease_qlen(child, child->q.qlen); 207 qdisc_destroy(child); 208 } 209 } 210 sch_tree_unlock(sch); 211 212 for (i=0; i<q->bands; i++) { 213 if (q->queues[i] == &noop_qdisc) { 214 struct Qdisc *child; 215 child = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue, 216 &pfifo_qdisc_ops, 217 TC_H_MAKE(sch->handle, i + 1)); 218 if (child) { 219 sch_tree_lock(sch); 220 child = xchg(&q->queues[i], child); 221 222 if (child != &noop_qdisc) { 223 qdisc_tree_decrease_qlen(child, 224 child->q.qlen); 225 qdisc_destroy(child); 226 } 227 sch_tree_unlock(sch); 228 } 229 } 230 } 231 return 0; 232 } 233 234 static int prio_init(struct Qdisc *sch, struct nlattr *opt) 235 { 236 struct prio_sched_data *q = qdisc_priv(sch); 237 int i; 238 239 for (i=0; i<TCQ_PRIO_BANDS; i++) 240 q->queues[i] = &noop_qdisc; 241 242 if (opt == NULL) { 243 return -EINVAL; 244 } else { 245 int err; 246 247 if ((err= prio_tune(sch, opt)) != 0) 248 return err; 249 } 250 return 0; 251 } 252 253 static int prio_dump(struct Qdisc *sch, struct sk_buff *skb) 254 { 255 struct prio_sched_data *q = qdisc_priv(sch); 256 unsigned char *b = skb_tail_pointer(skb); 257 struct tc_prio_qopt opt; 258 259 opt.bands = q->bands; 260 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX+1); 261 262 NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt); 263 264 return skb->len; 265 266 nla_put_failure: 267 nlmsg_trim(skb, b); 268 return -1; 269 } 270 271 static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, 272 struct Qdisc **old) 273 { 274 struct prio_sched_data *q = qdisc_priv(sch); 275 unsigned long band = arg - 1; 276 277 if (band >= q->bands) 278 return -EINVAL; 279 280 if (new == NULL) 281 new = &noop_qdisc; 282 283 sch_tree_lock(sch); 284 *old = q->queues[band]; 285 q->queues[band] = new; 286 qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); 287 qdisc_reset(*old); 288 sch_tree_unlock(sch); 289 290 return 0; 291 } 292 293 static struct Qdisc * 294 prio_leaf(struct Qdisc *sch, unsigned long arg) 295 { 296 struct prio_sched_data *q = qdisc_priv(sch); 297 unsigned long band = arg - 1; 298 299 if (band >= q->bands) 300 return NULL; 301 302 return q->queues[band]; 303 } 304 305 static unsigned long prio_get(struct Qdisc *sch, u32 classid) 306 { 307 struct prio_sched_data *q = qdisc_priv(sch); 308 unsigned long band = TC_H_MIN(classid); 309 310 if (band - 1 >= q->bands) 311 return 0; 312 return band; 313 } 314 315 static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid) 316 { 317 return prio_get(sch, classid); 318 } 319 320 321 static void prio_put(struct Qdisc *q, unsigned long cl) 322 { 323 return; 324 } 325 326 static int prio_change(struct Qdisc *sch, u32 handle, u32 parent, struct nlattr **tca, unsigned long *arg) 327 { 328 unsigned long cl = *arg; 329 struct prio_sched_data *q = qdisc_priv(sch); 330 331 if (cl - 1 > q->bands) 332 return -ENOENT; 333 return 0; 334 } 335 336 static int prio_delete(struct Qdisc *sch, unsigned long cl) 337 { 338 struct prio_sched_data *q = qdisc_priv(sch); 339 if (cl - 1 > q->bands) 340 return -ENOENT; 341 return 0; 342 } 343 344 345 static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb, 346 struct tcmsg *tcm) 347 { 348 struct prio_sched_data *q = qdisc_priv(sch); 349 350 if (cl - 1 > q->bands) 351 return -ENOENT; 352 tcm->tcm_handle |= TC_H_MIN(cl); 353 if (q->queues[cl-1]) 354 tcm->tcm_info = q->queues[cl-1]->handle; 355 return 0; 356 } 357 358 static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl, 359 struct gnet_dump *d) 360 { 361 struct prio_sched_data *q = qdisc_priv(sch); 362 struct Qdisc *cl_q; 363 364 cl_q = q->queues[cl - 1]; 365 if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 || 366 gnet_stats_copy_queue(d, &cl_q->qstats) < 0) 367 return -1; 368 369 return 0; 370 } 371 372 static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg) 373 { 374 struct prio_sched_data *q = qdisc_priv(sch); 375 int prio; 376 377 if (arg->stop) 378 return; 379 380 for (prio = 0; prio < q->bands; prio++) { 381 if (arg->count < arg->skip) { 382 arg->count++; 383 continue; 384 } 385 if (arg->fn(sch, prio+1, arg) < 0) { 386 arg->stop = 1; 387 break; 388 } 389 arg->count++; 390 } 391 } 392 393 static struct tcf_proto ** prio_find_tcf(struct Qdisc *sch, unsigned long cl) 394 { 395 struct prio_sched_data *q = qdisc_priv(sch); 396 397 if (cl) 398 return NULL; 399 return &q->filter_list; 400 } 401 402 static const struct Qdisc_class_ops prio_class_ops = { 403 .graft = prio_graft, 404 .leaf = prio_leaf, 405 .get = prio_get, 406 .put = prio_put, 407 .change = prio_change, 408 .delete = prio_delete, 409 .walk = prio_walk, 410 .tcf_chain = prio_find_tcf, 411 .bind_tcf = prio_bind, 412 .unbind_tcf = prio_put, 413 .dump = prio_dump_class, 414 .dump_stats = prio_dump_class_stats, 415 }; 416 417 static struct Qdisc_ops prio_qdisc_ops __read_mostly = { 418 .next = NULL, 419 .cl_ops = &prio_class_ops, 420 .id = "prio", 421 .priv_size = sizeof(struct prio_sched_data), 422 .enqueue = prio_enqueue, 423 .dequeue = prio_dequeue, 424 .requeue = prio_requeue, 425 .drop = prio_drop, 426 .init = prio_init, 427 .reset = prio_reset, 428 .destroy = prio_destroy, 429 .change = prio_tune, 430 .dump = prio_dump, 431 .owner = THIS_MODULE, 432 }; 433 434 static int __init prio_module_init(void) 435 { 436 return register_qdisc(&prio_qdisc_ops); 437 } 438 439 static void __exit prio_module_exit(void) 440 { 441 unregister_qdisc(&prio_qdisc_ops); 442 } 443 444 module_init(prio_module_init) 445 module_exit(prio_module_exit) 446 447 MODULE_LICENSE("GPL"); 448